Hi OCN! I'm back!





I am currently in the process of setting up my new 2' x 3' CNC router. This machine was constructed according to the designs of Ahren Johnson and Nate Lowrie, using their custom machined parts. These two outstanding gentlemen teamed up to form Fine Line Automation(FLA). You can find the open source plans for the the 2' x 3' router at www.finelineautomation.com, which is the same place that sells kits and parts for replicating their CNC router.

Also, I'd like to give a special shout out to Cattle Rustler- I'm testing out his build log creator software and so far all is going well!

I will be keeping a (somewhat) brief log of my experience assembling and testing my machine while also attempting to provide assembly instructions as the plans from FLA are somewhat lacking in this regard. If you download the open source plans, you will find a well organized Bill of Materials, some PDFs detailing how the 80/20 must be machined if you are processing your own 80/20, and finally a 3D E-Drawing. Essentially, you're given a list of parts and a picture of what it's all supposed to look like when you're done.

I decided to cut, drill, and tap my own 80/20 frame which I purchased from the 80/20 surplus e-bay store. I also bought aluminum bars from McMaster-Carr to make my own rails instead of buying the steel rails from FLA. Unless you have a drill press and you are a skilled machinist, I would highly recommend buying the 8020 and steel rails from FLA. I spent the past week processing 8020 and making the rails. It was a lot of work and involved much frustration. In the end I was able to make do with a hand held drill and a few clever drill jigs constructed from scrap aluminum, utilizing squares and lots of clamps. I saved around $400 in materials but that really wasn't enough to make up for time and frustration.

Ok, that's enough of an introduction! On with the build!

Specs:
Sturdy 80/20 Aluminum Frame Sporting a 2' x 3' Workable Area
Hitachi M12VC 2-1/4-Horsepower Variable Speed Router
Custom Router Mount for Hitachi M12VC by K2CNC
Gecko G540 Stepper Motor Controller
3x 380 oz-in Nema 23 Stepper Motors
350W 48V Power Supply
Custom Machined Mounts, Bearing Blocks, and Carriages from FLA

I began by laying out the 80/20 base frame for the table, which I constructed upside down. First I took twelve 5/16" 18 BHCS (0.625" long) and screwed them half way into the ends of the horizontal pieces. There are two bolts in each circled end:


Next you will need four economy T-nuts, two 2" long carriage bolts, and two 5/16" 18 BHCS. It is important that you gather all the parts that need to slide into the 24" cross beams from the ends. This has to be done now, or you will find yourself disassembling the entire frame in about an hour or so once you realize your mistake:


Slide the carriage bolts into the rear 24" cross beam. We won't need these until later, but it will be impossible to get them into the 8020 channel after the main frame has been bolted together:


Note the location of the carriage bolts, front and center:


Slide two T-nuts into the outward-facing channel of the front 24" cross beam. These will be used for mounting the stepper motor:


The same two T-nuts are circled in this picture for reference:


Slide the T-nuts and BHCS into the central 24" cross beam. I found it is much easier to do it this way than to try to screw the bolts into the nuts after the nuts have been put in place:


Slide the 14" 8020 beam over the BHCS you just put in place, forming a T like so:


Then use a hex key and the access holes drilled in the 14" 8020 beam to tighten the screws. Tighten just enough so the pieces do not come apart on their own but leave it loose enough so there is still some play:


Take two more 5/16" 18 BHCS (0.625" long) and screw them part way into the other end of the 14" beam:


Slide the front 24" beam over the bolts you just screwed into the end of the 14" beam and use the access holes in the front beam to tighten the bolts:


Next you want to slide the 45" side beams over the center cross beam. This is the before picture:


This is after. Do not slide it in all the way yet because we still need to install the feet.


Take your four 6" pieces of 8020 (or whatever you are using for legs) and screw two 5/16" 18 (0.625" long) BHCS into one end of each leg:


Then slide the legs into position:


All four legs in place:


Now you can slide the two outer cross beams into the side rails. At this point you are going to want tighten every single bolt holding the frame together. It would probably be a good idea to check everything with a square. Resist the temptation to flip the frame over and tighten the bolts holding the legs in place.


For the next step you need the 40.5" threaded Acme rod, one anti-backlash nut, a bearing block with bearing, bearing block cover, four washers, two needle thrust bearings, a 3.25" long 1/2" steel rod, a 1/2" shaft coupler, 1/2" clamp collar, four nylon lock nuts, two 1/4" 20 x 0.625" SHCS, two 2" carriage bolts, and a 1/2" to 1/4" anti-backlash shaft coupler:


Insert the 1/2" steel rod in the bearing block. There should be roughly equal lengths protruding from both sides of the bearing block:


Next place the bearing block cover plate over the steel rod and secure it with the two 1/4"-20 SHCS:


Place a washer on top of the bearing plate:


Add a needle thrust bearing on top of that:


...another washer...


and finally the 1/2" shaft coupler.


Flip the piece around and add another washer-needle thrust bearing-washer sandwich to the other side of the bearing block:


secure it with a 1/2" clamp collar:


and top it off with a 1/2" to 1/4" anti-backlash shaft coupler:


Find another bearing block, cover, and two more 1/4"-20 SHCS:


Install the cover on the bearing block:


Thread the anti-backlash nut a few inches along the 40.5" Acme rod:


Slide the two carriage bolts into the 14" 8020 beam:


Slip the bearing block with the shaft couplers over the carriage bolts, slide it to the front of the frame:


The 1/4" end of the 1/4" to 1/2" shaft coupler should line up with the outer face of the front 8020 cross piece:


Install the two nylon locking nuts(hand tight for now) and insert the threaded Acme rod into the 1/2" shaft coupler:


Everything should look like this:


Take your second bearing block and slip it over the other end of the Acme rod:


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